Field of the Invention
This invention relates generally to image sensors and displays. In addition, this invention relates to wearable technology including image sensors and displays, and more particularly to head mounted displays (HMDs) including image sensors and displays.
Description of the Background Art
As wearable technology becomes more popular, it is increasingly important for manufacturers to design gadgets that are as comfortable and functional as possible. Head mounted displays (HMDs) are a form of wearable technology that is worn on the head, often mounted to a user's glasses or other type of headwear. Users typically interact with HMDs using voice commands or via buttons/touchpads on the device. It is desirable for users to interact with HMDs in other ways, such as by gesturing with hands or eyes.
Currently, HMDs are capable of tracking users' eye movements and associating those movements with specific actions, such as taking a picture or opening a notification. Known HMDs utilize an infrared (IR) light source, positioned to direct IR light onto the eye of the wearer. This light reflects off the eye and onto an IR sensor, which detects, in real time, whether the eye is open or closed, and, if open, in which direction the pupil is pointing. This allows the user to interact with the device simply by looking at objects, blinking, etc.
Another important capability of HMDs is the ability to display visible information to the user. This information is projected directly into the user's eye, such that visual information projected by the device will appear seamlessly in the user's surroundings. Current HMD's utilize a liquid crystal on silicon (LCOS) display, a light source, and optics to display images.
Significant drawbacks of current HMDs include size and cost of manufacture. One proposed solution for minimizing the size and cost of an HMD is to place both the LCOS pixels and the IR sensor pixels on a single silicon die (a combination device) and using a common optical path to project images and detect IR light.
In known combination devices, groups of LCOS pixels and IR sensor pixels are arranged in alternating columns or in a checkerboard configuration. These configurations are problematic, because the IR sensor pixels create lines, dots, gaps, or other visible defects in the image generated by the LCOS display. Similarly, the LCOS pixels create lines, dots, gaps, or other visible defects in the image captured by the IR sensor pixels, thereby limiting the resolution and uniformity of the image captured by IR sensor and/or creating problems in eye detection. What is needed, therefore, is a combined LCOS display and IR sensor that reduces visible defects in a projected image. What is also needed is a combined LCOS display and IR sensor with improved IR sensor resolution and/or uniformity.